Hello from Hobart
And don't forget us folks in Tassie!
There's plenty of us here who are very familiar with GTD and its profound benefits. While folks are certainly making inroads into using GTD, I'm not aware yet of any black-belt practitioners; a visit by the David Allen Company would be most welcome!
I started out my GTD journey using the NetCentrics add-in for Outlook, but have since moved to the Apple ecosystem (= OmniFocus). After a year or so off the GTD wagon, when I lived mostly in emergency-scanning mode, I've just bought an iPad and am finding that OmniFocus works much better for me with this tool and its human-friendly interface than with the Mac (I'm so over the mouse as a control tool - bring on the Minority Report style computer interface I say!).
Other GTD-related tools for me include Dropbox, Zenbe Lists and of course iCloud for centralising email, calendars and contacts. Will investigate Evernote as a tool for reference and project-support material and need to look into some outlining/brainstorming tools as well.